Device for buttwelding metal sheets



19 M. BACROIX 3,265,277

DEVICE FOR BUTTWELDING METAL SHEETS Filed Jan. 23, 1964 2 Sheets-Sheet 1 a 4 fig] n 19 1o 7 2 2O 69 15; 8 T/ 17 I 9 i 11 10 \V 2 w\ /Z t Marcel BA CR OiX Maw '4 Aug. 9, 1966 M.- BACROIX DEVICE FOR BUTTWELDING METAL SHEETS 2 Sheets-Sheet 2 Filed Jan. 23, 1964 Q U Q m m N 741 venl r United States Patent Claims. (Cl. 22844) The present invention relates to devices for buttwelding metal sheets in a continuous manner and more particularly to those of the type which comprises at least one pair of forging or pinching rollers which pinch the edges of the sheets urged toward each other.

Owing to the forging force they exert on the edges of the sheets the forging rollers, Whose axes of rotation are oblique relative to the surface of the sheets tobe welded, are subjected to thrusts applied in a direction parallel with their axes and at a certain distance therefrom. These thrusts tend to tilt the rollers on their journals and create wear in these journals and consequently play between the journals and rollers which accentuates the tilting tendency. Consequently, the rollers are no longer applied against the edges of the sheets and the latter can become offset from each other instead of remaining in perfect alignment.

The object of the invention is to provide a device for buttwelding metal sheets in a continuous manner by bringing together edges of said sheets in the heated condition, said device being of the aforementioned type and comprising at least one pair of forging rollers mounted in an oblique manner on a common head and applied against the edges of the sheets to be welded, said device being so improved as to preclude the tilting of the forging rollers on their journals and to maintain with respect to time the rollers suitably applied against said edges of the sheets.

In the improved device according to the invention each forging roller is provided with a cylindrical bearing face and a thrust face, both of which are coaxial with the journal of the roller, the cylindrical bearing face of each roller rolling along the corresponding thrust face of the other roller of said pair of rollers.

By means of this-arrangement, the forging rollers are not only applied against the edges of the sheets but also against each other and this permits maintaining the sheets in perfect alignment irrcspective'of the wear of the journals.

Another object of the invention is to provide machines for Welding helically formed tubes and machines for welding tubes in the longitudinal direction which include the improved device defined hereinbefore.

Further features and advantages of the invention will be apparent from the ensuing description, with reference to the accompanying drawings to which the invention is in no way limited. In the drawings:

FIG. 1 is a diagrammatic view, with parts broken away, of the device according to the invention;

FIG. 2 is a view similar to FIG. 1, on a reduced scale, of a modification of the invention;

FIG. 3 is a view similar to FIG. 2 of another modification;

FIG. 4 is a plan view showing the application of the device according to the invention to a machine for helically welding tubes, and

FIG. 5 is a cross-sectional view of the application of the device according to the invention to a machine for welding tubes in the longitudial direction.

In the embodiment shown in FIG. 1, the device according to the invention is applied, to the continuous buttwelding of two metal sheets t t As is known, the edges of the chamfered sheets are heated by a device (not shown) which heats by resistance or a high-frequency current. The sheets are fed continuously by a roller feed device (not shown) and are brought together by pressure-applying means in the direction of arrows f and P, such as for example lateral rollers (not shown).

The device according to the invention comprises, as known per se, two upper forging rollers G and G and two lower counter forging rollers G and G all four of which are urged against the surface of the marginal portions of the sheets.

The upper rollers G and G are carried by a cylindrical head 1 suspended from a support. Only a portion or plate 2 of this support has been shown. For this purpose the cylindrical head 1 is extended by a screw 3 which extends through the suspension plate 2 and is locked against the latter by a nut. Spring steel washers 5, for example of the Belleville type, are mounted on the screw 3 and are compressed between the head 1 and the plate 2 so as to insure that the upper rollers G and G bear resiliently against the upper face of the edges of the sheets. These edges bear against the lower rollers G and G The cylindrical head 1 is rotatable about its vertical axis so that the rollers G and G are orientatable in the direction of feed of the sheets.

The head 1 carries two journals 6 whose axes TT and V-V intersect and are, for example, inclined at to the vertical. These journals carry bushings 7 on which are freely rotative the rollers G and G A retaining washer 8 secured by a screw 9 to each journal 6 prevents the roller from falling off the journal when it is not applied against the sheet t, or

As a result of this assembly, the rollers G and G are downwardly convergent. The roller G located adjacent the edge of the sheet t whose chamfered edge makes an acute angle with the upper face of the sheet, comprises an operative frustoconical face 10 which has an axis T-T and is tangent to this face of the sheet and an operative frustoconical face 11 which is normal to this face and has a base common with the frustoconical face 10. The latter has a width substantially greater than the width of the zone of the sheet which is locally heated so as to extend beyond this hot zone and be in contact with the neighbouring cold zone. The upper roller G located on the other side of the joint, that is, on the other edge to be welded, has the same frustoconical faces.

The lower counter rollers G and G are mounted on a vertical head '12 which is mounted for pivotal movement about its axis in a sleeve 13 carried by a stand. Only a portion or plate 14 of this stand has been shown. The plate 14 can rest on a resilient support (not shown). This mounting of the head 12 permits the rollers G and G to be orientated in the same manner as the rollers G and G in the direction in which the sheetst and t are fed.

The rollers G and G are freely rotative on bushings 15 carried by journals 1'6 rigidwith the head 12. These journals 16 have axes WW, Z-Z which intersect and are inclined, for example, at 30 to the vertical. The rollers G and 6.; have frustoconical forging faces which are similar to the faces 10 and 11 of the rollers G and G and carry the same reference characters.

According to the invention the rollers G G G and G comprise reciprocal bearing faces.

As concerns the upper rollers G and G the roller G comprises a plane thrust face 17 and a cylindrical bearing face 518 which has the same axis TT as the face 17 and is adjacent the latter. The roller G comprises a plane thrust face 19 and a cylindrical bearing face 20 which has the same axis VV as the" face 19 and is adjacent the latter. The cylindrical face 18 of the roller G bears against the plane face'19 of the roller G and the cylindrical face 20 of the roller G bears against the thrust face 17 of the roller G and vice versa.

The device operates in the following manner:

As is known, the continuously-fed sheets rotate the rollers G G G G The latter pinch the bead B of the edges of the sheets, which are urged together, while maintaining these edges in perfect alignment. As the sheets advance, the cylindrical bearing face 18 of the roller G rolls on the face 119 of the roller G and the. cylindrical bearing face 20 of the roller G rolls on the face 17 of the roller G Similarly, the cylindrical bearing faces of the rollers G and 6.; roll on corresponding frustoconical faces.

The forging force exerted by the rollers on the bead B of the edges of the sheets is supported in accordance with the invention by the cylindrical faces 18 and 20 of the rollers G and G and the corresponding thrust faces :17 and 19 and by the cylindrical faces 21 and 23 of the rollers G and G and the corresponding frustoconical faces 22 and 24. As the cylindrical faces are coaxial with the bearings and journals on which the forging rollers are'mounted, these journals are subjected to no radial stresses.

The cylindrical face 18 of the roller G receives in the radial direction the axial thrust of the roller G through the medium of the thrust face 19 of the latter and the cylindrical face 20 of the roller G receives in the radial direction the axial thrust of the roller G through the medium of the thrust face 17 of the roller G Similarly, the cylindrical face 21 of the roller G receives the thrust of the roller G through the medium of the face 24 of the latter and the cylindrical face 23 of the roller G receives the thrust of the roller G through the medium of the face 22 of the latter.

Thus, each upper or lower roller only receives from the other roller mounted on the same head a radial force with respect to its journal. The absence of axial thrust applied in an eccentric position with respect to the bearings 7 and 15 avoids the tilting of the rollers on their bearings. Owing to the faces 17-24 of the rollers G G G G the sole result of radial wear of the bearings, that is, radial play of the rollers on these bearings, is the simultaneous axial displacement of the rollers on their journals. As concerns each pair of rollers G -G and G G this displacement along the axes T-T, VV, W-W and ZZ has the same magnitude. Consequently, there is no possibility of a roller becoming olfset relative to another mounted on the same head. Thus, there is no possibility of the edges of the sheet becoming offset from each other and these edges always remain perfectly aligned.

Moreover, the wear in the bearings 7 and :15 is compensated by the Belleville washers or by any other elastically yieldable mounting of the head 1 or 12 which tends to urge the rollers G G G G against the sheets. This arrangement is particularly simple and robust.

Further, owing to the inclination of 30 of the lower forging rollers G and G relative to the edges of the sheets t and t the rollers G and G are rather close to these sheets and the sheet .14 supporting the head 12 can be placed nearer to said sheets. This is advantageous when space under the sheets is limited.

In the embodiment shown in FIG. 2, the rollers G and G are replaced by rollers G and G mounted on journals which are inclined at 45 to the vertical. Consequently, these rollers make an angle of 90 in the same manner as the upper rollers G and G Their support faces are therefore identical to those of the upper rollers. If space is not limited below the sheets this is an advantageous solution since there are only two types of rollers instead of four. Note, moreover, that the forging or pinching force exerted on the bead B is lower than in the arrangement shown in FIG. 1.

In the embodiment shown in FIG. 3, .the lower forging rollers are replaced by a single roller G having a generally cylindrical shape and comprising an operative cylindrical face 25 tangent with the face of the edges of the sheets to be welded and an annular groove 26 having a trapezoidal contour in line with the weld bead B. This single roller is freely rotative between the branches of a fork 27 having a vertical pivot mounted on the sleeve 13. This embodiment has the double advantage of cheapness and the fact that only a small amount of space is occupied below the sheets.

FIGS. 4 and 5 show by way of examples two applications of the device according to the invention.

In the example shown in FIG. 4, the invention is applied to a machine for welding helically wound tubes T consisting of a continuous helical coil of a sheet metal strip t. The machine is of known type and continuously welds the edges of the last coil s formed to the adjacent edges of the coil s being formed so as to form the tube T This machine comprises (a) a feed device for feeding the strip 1 which has not been shown for reasons of clarity; (b) a forming device for coiling the strip in the form of a spiral consisting for example of a cylindrical forming structure having an axis XX and an inner surface corresponding to the outer surface of the tube T to be obtained; this structure consists for example of plates 28 in spaced relation and carried by the stand 29 of the machine; (c) a localized heating device for heat ing the edges of the strip to be welded; this device is for example composed of two contacts 30 applied against the adjacent edges of the coils s and s and supplying "a high-frequency alternating current; (d) forging rollers for forging the bead of the edges of the strips, these rollers being shown in dotted line and mounted in the following manner: the suspension plate 2 of the upper cylindrical head 1 (not shown in FIG. 4) constitutes the bed of the stand 29 of the machine; the lower cylindrical head 12 is mounted at one end of a horizontal beam 31 which is parallel with the axis X-X and is located inside the coils being formed; this beam is carried by a carriage 32 which is vertically slidable on the stand.

FIG. 5 shows the application of the device of the invention to a welding machine welding tubes in the longitudinal direction. The tube T which is bent in a press (not shown) is fed in the longitudinal direction so as to bring together and weld its abutting edges on a rectilinear generatrix. The device for heating the edges to be welded can comprise two contacts supplying highfrequency current (not shown). The forging rollers for the weld bead are, for example, of the typev shown in FIG. 2. The suspension plate 2 for the upper head 1 is secured to the bed of the stand 33 of the machine. The lower head 12 is mounted on a sleeve 13 at one end of a horizontal beam 34.

Although specific embodiments of the invention have been described, many modifications and changes may be made therein without departing from the scope of the invention as defined in the appended claims.

Thus, instead of spring steel washers 5 any other elastically yieldable device could be employed, for example a hydraulic jack or flexible suspension plate 2. Further, the forging rollers can be inclined at different angles in accordance with the available space and with the desired pinching force to be exerted on the weld bead.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. A device for continuously forming a buttwelded joint between the heated edges of metal sheets, comprising a head, a pair of forging rollers rotatably mounted on the head and located on each side of the joint, the

axes of rotation of the rollers being at an angle to each other, each roller having a Work engaging face, a cylindrical bearing face and a thrust face, all of said faces being coaxial on they axis of rotation of the roller, and the cylindrical bearing face of each roller bearing against the thrust face of the other roller of said pair of rollers.

2. A device for continuously forming a buttwelded joint between the heated edges of metal sheets, comprising a head, a pair of forging rollers rotatably mounted on the head and located on each side of the joint, the axes of rotation of the rollers being at an angle to each other, each roller having a work engaging face, a cylindrical bearing face and a plane thrust face, all of said faces being coaxial on the axis of rotation of the roller, and the cylindrical bearing face of each roller bearing against the thrust face of the other roller of said pair of rollers.

3. A device for continuously forming a buttwelded joint between the heated edges of metal sheets, compris .ing a head, a pair of forging rollers rotatably mounted on the head and located on each side of the joint, the axes of rotation of the rollers being at an angle to each other, each roller having a Work engaging face, a cylindrical bearing face and a frustoconical thrust face, all of said faces being coaxial on the axis of rotation of the roller, and the cylindrical bearing'face of each roller bearing against the thrust face of the other roller of said pair of rollers.

4. In a machine for continuously Welding a helically coiled strip into a tube, means for heating the adjoining helical edges of two adjoining coils of the strip, and a device for continuously forming a buttwelded joint between said heated edges, said device comprising a head, a pair of forging rollers rotatably mounted on the head and located on each side of the joint, the axes of rotation of the rollers being at an angle to each other, each roller having a Work engaging face, a cylindrical bearing face and a thrust face, all of said faces being coaxial on the axis of rotation of the roller, and the cylindrical bearing face of each roller bearing against the thrust face. of the other roller of said pair of rollers.

5. In a machine for continuously welding the adjoining longitudinal edges of a strip bent into the form of a tube, means for heating said adjoining edges, and a device for continuously forming a buttwelded joint between said heated edges, said device comprising a head, a pair of forging rollers rotatably mounted on the head and located on each side of the joint, the axes of rotation of the rollers being at an angle to each other, each roller having a work engaging face, a cylindrical bearing face References Cited by the Examiner UNITED STATES PATENTS 1,443,123

1/1923 'Giorgini 2l981 FOREIGN PATENTS 163,249 6/1949 Germany.

CHARLIE T. MOON, Primary Examiner.

M. L. FAIGUS, Assistant Examiner. 

1. A DEVICE FOR CONTINUOUSLY FORMING A BUTTWELDED JOINT BTWEEN THE HEATED EDGES OF METAL SHEETS, COMPRISING A HEAD, A PAIR OF FORGING ROLLERS ROTATABLY MOUNTED ON THE HEAD AND LOCATED ON EACH OF THE JOINT, THE AXES OF ROTATION OF THE ROLLERS BEING AT AN ANGLE TO EACH OTHER, EACH ROLLER HAVING A WORK ENGAGING FACE, A CYLIN- 